Users of data processing systems receive or access information on various subjects, from a number of sources and in various formats. Users also generate or modify documents, images, and other types of information which are saved in local storage associated with the user's computer. This enables the user to view and modify the data without needing to be connected to the network. The different types of data are stored in various places on a user's computer system and are viewed and managed by a variety of application programs —each of which is best suited to one particular type of data. Users also work with data and applications which are distributed over two or more computer systems. The data or the applications, or both, may reside on a computer separate from the user's computer system.
Each of the data types is normally organised into its own hierarchical information space. The user creates a taxonomy of folders in which to store copies of e-mails. The user also generates a similar (but seldom identical) taxonomy for organising bookmarks in their chosen browser. Furthermore, the user divides their local drives into hierarchical directory/folder structures. All these structures were influenced by the user's mental model of how things are related, and it is frequently the case that each structure has some features in common with the other data structures that the user has created for other types of data. Nevertheless, the hierarchical data organisation is seldom (if ever) identical across multiple applications.
Maintaining these different types of data and organising the data that is received from the different applications is an onerous task, unless the different data can be organised in a consistent manner so that navigation and management is easier for the user. One approach to try and achieve consistency and hence reduce future workload is to attempt to unify all received data into one format and then access it using one particular application program. This approach of transforming data to a single format (which could be labelled as “coercion”) would require parsing and transformation of most data feeds including data conversion. The coercion approach would present a significant processing overhead and would probably run into conversion problems.
It is also known to “federate” various data sources, so that they appear to be one (logical) data source. Federation is a technique which is used with multiple data sources which differ slightly in terms of detailed representation but not in terms of gross characteristics. Heterogeneous database management systems are a good example of such sources. Federation can be achieved by interposing an additional layer of abstraction between the physical data and one application program which is used to view and manage it. However, the addition of this extra level of abstraction adds undesirable complexity and processing to the user's computer system and could suffer from similar problems to those that afflict the coercion approach. Furthermore, automated federation typically combines independent data sources without taking account of similarities between each source's data organisation.
Both of the previous approaches suffer from the problem that new or modified data formats and advances in the application programs normally used to manipulate each type of data are unlikely to be readily available in either a coerced or a federated system. For these reasons, it remains preferable to use the “native” application program for each type of information. (Examples of ‘application programs’ in this context are Microsoft's Internet Explorer or Netscape's Navigator for Web browsing, Microsoft® Outlook for e-mail, or Lotus Notes® software for e-mail and data management. Lotus Notes is a trademark of International Business Machines Corporation, Microsoft is a trademark of Microsoft Corporation in the United States, other countries, or both.)
There exists a need for a solution which simplifies the management of data by providing consistency of data organisation for different data types, without the disadvantages of known coerced or federated approaches.